In a wide variety of circumstances, animals, including humans, can suffer from bleeding due to wounds or during surgical procedures. In some circumstances, the bleeding is relatively minor, and normal blood clotting functions in addition to the application of simple first aid are all that is required. In other circumstances substantial bleeding can occur. The control of bleeding is essential and critical in surgical procedures to minimize blood loss, to reduce post-surgical complications, and to shorten the duration of the surgery in the operating room.
Known hemostatic and sealant materials include absorbable liquid sealants such as fibrin sealants which are formed from blood plasma components and comprise a first agent containing fibrinogen and a second agent which usually includes thrombin. Fibrinogen is capable of a polymerizing to form a solid fibrin clot when the agents are mixed. Other hemostatic materials for controlling excessive bleeding include Topical Absorbable Hemostats (TAHs) which are widely used in surgical applications. TAHs encompass products based on oxidized cellulose (OC), oxidized regenerated cellulose (ORC), gelatin, collagen, chitin, chitosan, etc. These materials can be delivered in solid form, as scaffolds, as suspensions or paste, or as powders.
Application of any medicants, including biological sealants, to target areas, requires accurate mixing and targeting, particularly when a multi-part sealant is used, due to the rapid polymerization upon interaction of the components. For delivery of fibrin sealant, for example, the two components are typically dispensed simultaneously from separate devices, such as syringes, and mixed together immediately prior to application or on the tissue surface.
Gas-assisted application of sealant, such as through use of a syringe described above, is frequently used to deliver the sealant to the desired site, and sometimes pressurized and atomized application of the sealant is useful. For spraying fluids, such a multi-part sealant, as well as for spraying powders, mixing, accuracy, and efficiency of the spraying is frequently helped by use of compressed gas. Gas-assisted spray uses gas pressure to spray the material directly at the intended site, helping targeted delivery, atomization, and ease of application. A pressurized, typically sterile gas, such as air, nitrogen, carbon dioxide, and the like, atomizes and propels the sprayed material towards the surface of the tissue.
Maintaining optimal distances from the dispensing nozzle to the treated areas of tissue during dispensing of the tissue sealants and hemostats is important for optimal mixing of the components, optimal spray patterns, and, especially but not only in cases of gas-assisted delivery, for avoiding gas embolisms. Maintaining optimal distances is especially important during laparoscopic delivery due to difficulties in reliably estimating distances in a laparoscopic environment.
U.S. Pat. No. 6,461,361 “Gas-driven spraying of mixed sealant agents”, discloses that a gas-driven spray applicator suitable for spray delivery of mixed fibrin sealants for surgical use has a spray nozzle wherein droplets or a stream of mixed sealant agents are entrained in a stream of gas such as sterile compressed air. Gas entrainment of the mixed sealant overcomes problems of ineffective mixing which may occur when the sealant agents are separately discharged into overlapping spray patterns. A spray tip assembly is disclosed which is suitable for attachment to an applicator body having manually dischargeable reservoirs for the sealant agents.
U.S. Pat. No. 6,461,361 further discloses a spray applicator for spraying a liquid sealant comprising at least two sealant agents capable of coagulating when mixed together, the applicator comprising: a) a spray hood defining a spray volume; b) a sealant delivery pathway extending from individual sources of the respective sealant agents to the spray volume for delivery of the at least two sealant agents to the spray volume; c) a pressurized gas inlet to generate a gas stream into the spray volume, wherein the sealant delivery pathway can deliver the at least two sealant agents to the gas stream to generate a spray containing the at least two sealant agents, wherein the pressurized gas inlet is connectable to a source of pressurized gas being a compressed air supply, a surgical operating room gas supply or a portable container of compressed gas; and d) a spacer element extending in the direction of spraying to maintain a desired distance between the spray volume and a work surface.
U.S. Pat. No. 6,461,361 further discloses a spray tip assembly intended to be attached to a spray applicator body to provide a spray applicator for spraying a liquid sealant comprising at least two sealant agents capable of coagulating when mixed, the applicator body having: a) at least two reservoirs respectively for storing the at least two sealant agents; b) at least two conduits for separately dispensing the at least two sealant agents; and c) a manually actuatable dispensing mechanism to discharge the sealant agents from the reservoirs through the at least two conduits; d) at least two sealant agent receiving ports connectable with the at least two conduits; e) a mixing chamber to receive and mix the at least two sealant agents from the at least two sealant receiving ports to provide mixed sealant; f) a spray hood defining a spray volume; g) a delivery conduit to receive mixed sealant from the mixing volume and deliver the mixed sealant to the spray volume; h) a pressurized gas inlet to generate a gas stream into the spray volume; wherein the delivery conduit extends into the path of the gas stream to deliver the mixed sealant to the gas stream, to generate a spray of mixed sealant droplets; and i) a spacer element extending in the direction of spraying to maintain a desired distance between the spray volume and a work surface. The assembly described is bulky, not laparoscopically deployable, can interfere with the spray, and prevents the spray performed closer to the surface when no gas assist is used.
U.S. Pat. No. 6,641,558 “Method and apparatus for preventing air embolisms” discloses method and apparatus for preventing air embolisms during surgical procedures which involves providing a fluid source in communication with an aperture extending into an anatomical cavity such that fluid may be delivered into the cavity when a condition of negative pressure exists in the cavity, thereby preventing the introduction of air into the cavity.
U.S. Pat. No. 4,722,725 “Methods for preventing the introduction of air or fluid into the body of a patient” discloses a method for preventing the introduction of ambient air into the vascular system of a patient through catheter means introduced into said vascular system during intravenous or intra-arterial procedures which comprises: providing the catheter means with fluid flow control means comprising: a tubular structure including input means and output means; each provided with an open bore constituting a flow channel; and further means located between the bores of said input and output means of said tubular structure and having an open and a closed position, said further means providing for a connecting channel between said bores when said further means is in the open position, said further means normally being prestressed to said closed position and being forcible to said open position in response to a positive fluid pressure in the bore of either of said input or output means, said further means being constructed and arranged so as to return to said closed position in response to a removal of positive fluid pressure from said bore containing same; introducing the catheter into the vascular system of the patient during intravenous or intra-arterial procedures; and introducing a fluid into said patient through said fluid flow control means and catheter means by directing the fluid under a positive pressure above that of ambient air into the bore of the input means of said fluid flow control means so that the fluid flow control means remains competent in response to ambient air pressure in the bore of said input means but which opens in response to said positive fluid pressure to allow flow therethrough, while also preventing the introduction of air into the vascular system of the patient.
U.S. Pat. No. 6,106,497 “System and method for preventing an air embolism in a surgical procedure” discloses a system for preventing an air embolism in the brain of an animal in a cardiovascular surgical procedure, comprising: a) a source of a gas; b) a mechanism for controlling pressure and flow of the gas therethrough, having an inlet end and an outlet end, the inlet end being connected to the gas source; and c) a tube for conveying the gas therethrough having a first end and a second end, and a member for preventing blood from flowing from the heart into the gas conveying tube; the first end adapted for placement in the heart of the animal and having a plurality of apertures for passage of the gas therethrough into the heart; wherein the pressure/flow controlling mechanism is disposed between the gas source and the gas conveying tube; and the gas source, the pressure/flow controlling mechanism and the gas conveying tube are in fluid flowing communication for conveying the gas therethrough; and the pressure/flow controlling mechanism is operable to provide a flow of the gas through the system such that when the first end of the gas conveying tube is placed into the heart, the pressure and flow of the gas from the pressure/flow controlling mechanism through the gas conveying tube into the heart is effective to inhibit air from entering the heart, great vessel, or both, or to remove air from the heart, the great vessel, or both.
U.S. Pat. No. 5,849,005 “Method and apparatus for minimizing the risk of air embolism when performing a procedure in a patient's thoracic cavity” discloses a method of minimizing the risk of air emboli in a patient's circulatory system when performing a procedure in the patient's thoracic cavity, comprising the steps of: inserting an instrument delivery member into a patient's thoracic caviler thereby forming a first percutaneous penetration, the instrument delivery member having a through hole sized to permit an instrument to pass therethrough; coupling an outlet from a source of gas to the instrument delivery member; injecting the gas from the source of gas into the patient's thoracic cavity through the outlet coupled to the instrument delivery member, the injecting step being carried out with a plurality of outlets coupled to the instrument delivery member for passing the gas into the patient's thoracic cavity, the injecting step being carried out so that the gas issuing from the plurality of outlets forms a gas shield across the through hole.
There is an unmet need in sealant or hemostat dispensing devices that are ensuring that spray is preformed not closer than the minimum recommended spray distance.